1. Field of the Invention
The present invention relates to an antiglare film and a manufacturing method thereof.
2. Description of the Related Art
Optical films of liquid crystal displays have been improved, with high contrast, wide viewing angles, high luminance, thinness, large sizes, higher precision, and other market demand functions. For display devices, display quality can be improved and scratch-resistant can be achieved with surface treatments for functional optical films. Optical films can be used for anti-glare, hard coating, anti-static, or anti-reflection purposes, based on their characteristics for improving dots per inch, contrast, and brightness. Since display devices are used in environments with external light, viewing quality is hindered by glare due to reflection of light. Thus, the optical film surface is treated for anti-glare and anti-reflection for decreasing reflection issues caused from external light, especially in bright environments, and improving viewing quality.
An effective method for controlling external light reflection may comprise treating optical films with an anti-glare treatment to diffuse the external light reflection or with an anti-reflection treatment to decrease light reflection intensity. Without surface treatment, 4-5% of external lights is reflected in the display device when the display device is being used. Normally, when users look at computer monitors, light reflection and glare on computer monitors makes viewing extremely uncomfortable for users. Thus, anti-glare characteristics of antiglare film are used and formed from an inner light diffusion structure or external light diffusion structure, or combinations thereof. The inner diffusion structure can be obtained by using various materials with different refraction indexes in the anti-glare film. The light scattering degree in the antiglare film can be controlled by adjusting the refraction index differences, content or size of the materials. The light scattering degree can also be controlled with an external diffusion structure by adjusting the shape or rough degree of the rough surface of the anti-glare film. Therefore, with the rough surface, the antiglare film allows the external diffusion structure to scatter light that would normally be directed toward user's eyes. Additionally, with different refraction index materials formed in the inside of the optical film, the optical film with the inner light diffusion structure, also scatters the light that would normally be directed toward user's eyes.
In conventional approaches, micro-particles of different sizes are added in a resin system for fabricating the anti-glare film. Although the particles are primarily dispersible in the resin system, phase separation occurs due to precipitation of the particles when the resin system is left standing. As a result, the dried coating suffers from a non-uniform quality and low process yield. For example, U.S. patent application Ser. No. 20040053043 describes an anti-glare film formed by adding micro-particles with diameters of 2-5 μm and 0.5-1.2 μm into a resin layer, and U.S. patent application Ser. No. 20060092495 describes an anti-glare film formed with a polymer compound solution containing micro-particles with diameters of 2-8 μm.